Mounted search and rescue

["wendy" <sar@summitgoats.com>]

 

Were you under dense cover?  This can cause inaccuracy in some GPS units.

 

Were you all on the same datum?  And using the same coordinate format?  (even if you are all on lat long, it could be dd mm sss or dd mm.mmm, etc.

 

If you had a consistent amount of error, it was probably a datum issue.  You need to set the datum to match *before* you enter your coordinates.  Any coordinates in the gps when you change the datum will be converted to the new datum (ie. They will show different coordinate numbers, but if you go to them they will be the exact same patch of earth as before.)

 

If you use a computer to download/upload your coordinates you can also avoid the datum-mix-up problem.  

 

 

Wendy– NREMT-P

Breeze – SAR, HIC, CGC and RANCH dog.

SummitPack Goats  www.summitpackgoats.com

It's not what we don't know that gets us in trouble, but what we are absolutely sure of that simply isn't true.

 

-----Original Message-----
From: Chuck Daniel [mailto:iwhound@voyager.net]
Sent: Tuesday, February 27, 2007 2:43 PM
To: MSAR-Riders@lists.ibiblio.org
Subject: [MSAR] GPS Tip

 

Over the past weekend, our group did some routine GPS training in the form of a treasure hunt.  What should of gone smoothly turned out poorly.  Here is what happened.  One in our group set out the course, depositing the treasures and recording the latitude and longitude of each treasure (way points).  She returned and gave us the coordinates and we inputted them into our GPS units.  We broke into teams and off we went.  My team found the first two locations but that may of been by luck since we noted that in each case the coordinates were off by 30 seconds in both lat and long.

The rest of the treasures were never found because of the 30 seconds error.  A 30 second error is over a half mile of error.  What we learned from this is that we need to compare all GPS units periodically.

 

Chuck Daniel

KVMSAR